LEDs offer several advantages over traditional light sources such as incandescent lamps. For example, LEDs have low power consumption, high power efficiency and long life. Therefore, there is a trend to replace incandescent lamps with LEDs. LED bulbs have similar shapes and sizes as those of incandescent bulbs. LED light sources and control circuitry are integrated within an LED bulb. Using a conventional on/off switch, a user can only control the on/off or brightness level of an LED bulb, but cannot adjust the color of the light. In order to adjust the color, a special dimmer or a remote controller is needed.